1. Field of the Invention
The invention relates to a medium library apparatus, and more particularly to a medium library apparatus having a plurality of cells into each of which is loaded a medium. Herein, a medium means a cartridge containing a magnetic tape wound therein, a magnetic disc and so on.
2. Description of the Related Art
FIGS. 1A and 1B illustrate one of conventional cartridge library apparatuses suggested in Japanese Unexamined Patent Publication No. 2-81352. The suggested cartridge library apparatus is embodied as a library apparatus for loading a magnetic tape cartridge thereinto.
The cartridge library apparatus includes a plurality of shelves 1 each of which has oppositely located sidewalls to each of which a leaf spring 2 is connected. Each of the leaf springs 2 is designed to downwardly deform, and is formed at a distal end thereof with a projection 3 horizontally, inwardly extending from the each of the leaf springs 2. The projections 3 act as a latch by fitting into grooves (not illustrated) of a magnetic tape cartridge 4 having been loaded into the shelf 1.
When a magnetic tape cartridge 4 is loaded into a selected shelf 1 by means of an automatic handling equipment (not illustrated), the leaf springs 2 are downwardly deformed, and the magnetic tape cartridge 4 is loaded into the shelf 1 above the deformed leaf springs to thereby avoid the projections 3 from fitting into the grooves to thereby latch the magnetic tape cartridge 4. Thereafter, the magnetic tape cartridge 4 rests on a bottom surface of the shelf 1 by dead weight of itself. Then, the leaf springs 2 having been made to downwardly deform are allowed to return to their original shapes, resulting in that the projections 3 fit into the grooves of the magnetic tape cartridge 4. Thus, the magnetic tape cartridge 4 once having been loaded into the shelf 1 is prevented from leaving the shelf 1.
In accordance with the above-mentioned cartridge library apparatus, the magnetic tape cartridge 4 is automatically latched by the leaf springs 2. However, it is necessary to move the automatic handling equipment upwardly or downwardly in order to avoid the magnetic tape cartridge 4 from being latched or latch the magnetic tape cartridge 4. That is, the automatic handling equipment has to be moved upwardly or downwardly each time when the magnetic tape cartridge 4 is to be loaded into or taken out of the shelf 1.
Japanese Unexamined Patent Publication No. 6-162636 has suggested another cartridge library apparatus. FIG. 2 illustrates one of shelves 5 of the suggested cartridge library apparatus. The each of the shelves 5 is formed at a sidewall thereof and at an opening thereof with a stopper 6. The stopper 6 has a first portion 6a projecting inwardly of the shelf 5 and a second portion 6b projecting outwardly of the shelf 5. The stopper 6 is designed to rotate about a fulcrum 7 in directions indicated with arrows A and B. The second portion 6b of the stopper 6 is connected to a projecting portion 5a of the shelf 5 through a spring 8.
In operation, when a magnetic tape cartridge 9 is loaded into the shelf 5 by an automatic handling equipment (not illustrated), the stopper 6 is made to rotate in the direction A. Then, after the magnetic tape cartridge 9 has been completely loaded in the shelf 5, the stopper 6 returns to a position illustrated in FIG. 2 by a force of the spring 8. Thus, the stopper 6 prevents the magnetic tape cartridge 9 from being ejected out of the shelf 5. When the magnetic tape cartridge 9 is to be taken out of the shelf 5, the automatic handling equipment holds the magnetic tape cartridge 9, and then leaves the shelf 5. While the magnetic tape cartridge 9 is leaving the shelf 5, the stopper 6 is made to rotate in the direction B. After the magnetic tape cartridge 9 has left the shelf 5, the stopper 6 returns to a position illustrated in FIG. 2 by a force of the spring 8.
The above-mentioned Publication No. 6-162636 has suggested a cartridge library apparatus having a simpler structure than that of the cartridge library apparatus suggested in the firstly mentioned Publication. However, the cartridge library apparatus suggested in the Publication 6-162636 is accompanied with a problem that even after the magnetic film cartridge 9 has been once loaded in the shelf 5, the magnetic film cartridge 9 may be ejected out of the shelf 5, because the stopper 6 is designed to rotate in both the directions A and B.
Japanese Unexamined Utility Model Publication No. 61-6944 has suggested still another cartridge library apparatus. The suggested cartridge library apparatus includes a plurality of shelves into each of which a magnet tape cartridge is to be loaded and each of which has a bottom rotatable about one longitudinal edge thereof, and a driver means for driving the shelves between a first position where a bottom of the shelves are downwardly rotated and a second position where a bottom of the shelves are kept horizontally.
This cartridge library apparatus has a problem that each of shelves have to be designed to have a rotatable bottom, and that the cartridge library apparatus has to have the driver means for controlling the rotation of the shelves, both of which cause the cartridge library apparatus to be more complicated in structure and to operate in more complicated steps.